Here's the explanation from a Flash lettercolumn that I distinctly recall because it was so dopey: Because K%llg%re was a mathematical, rational being, it would see that "percent" sign as actually "zero divided by zero". And sinze zero divided by zero is nothing, those would produce no sound and it would be pronounced "Kllgre". I'm not sure if anybody ever wrote in to explain how THAT was pronounced.

there are several mistakes in the explanation that joe gave first of all the percent sign doesnt mean zero divided by zero (those are not zeroes) in mathematics it means module,secondly for "zero divided by zero" to be nothing it needs to be defined which it isn't in normal mathematics due to propreties of division and zero.